Probing nonlocal tracer dispersion in flows through random porous media
- 1 July 1996
- journal article
- research article
- Published by American Physical Society (APS) in Physical Review E
- Vol. 54 (1) , 656-660
- https://doi.org/10.1103/physreve.54.656
Abstract
Pulsed-field-gradient NMR is used to measure tracer dispersion in flow through a porous medium. Data are presented for water flowing through packs of plastic beads at Péclet numbers 0≤Pe≤150, using strong, fast gradient pulses to measure pore-scale molecular displacements. The transition at Pe∼1 from tortuosity-reduced diffusion to dispersion is observed. The data are Fourier transformed to provide a measurement of the wave-number- and frequency-dependent nonlocal dispersion coefficient. The experimental results compare favorably with an approximate calculation of Koch and Brady [J. Fluid Mech. 180, 387 (1987); Chem. Eng. Sci. 42, 1377 (1987)]. © 1996 The American Physical Society.Keywords
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